Okay so suppose I was going to max out on a deadlift or even just work up to a heavy single. Let's say my target weight was 400 for a single. This is porbably what my warmup would look like:

135x5
155x5
185x4 or 3
225x3 or 2
255x1
275x1
310x1
340x1
360x1
400x1

I feel like the lower weights help me out a lot, but am I doing too many warmups with heavier weights? I sometimes think they drain me of a lot of energy, however I've got this idea that going up really gradually gets my body accustomed to heavier loads and if I made bigger jumps the weight might feel shockingly heavy and difficult. Any thoughts?

Way too much volume for a single at 400. Your jumps from set to set are all over the place. You make little jumps and then big ones, back and forth, and finish off with the biggest jump (40 pounds) for your final set. Your CNS probably wonders wtf is going on. I'd do something more along the lines of:

45x10
135x1
185x1
235x1
285x1
335x1
375x1
400x1

If you wanted simplicity in loading the bar, I'd also accept this:

45x10
135x1
185x1
225x1
275x1
315x1
365x1
400x1

You could also hit triples for the first few sets, but that's more of a personal preference.

__________________If you don't get nervous before you train - you don't train hard enough.CrossFit Fredericton

For me it would depend on a couple things; whether I was working up to a true max or just a high effort single like a 90%. Also would depend on the lift, (push a pull or a press(. generally I feel better with short warm ups with big jumps. last week for a zercher squat max this is what worked.